Describe the events that take place in a neurone which produce an action potential
- The action potential begins when the stimulus exceeds the threshold.
- The voltage gated sodium ion channels open.
- Sodium ions diffuse into the axon down an electrochemical gradient.
- Positive feedback occurs (more sodium ion channels open).
- This depolarises the membrane.
- The membrane potential reverses from -65mV to +40mV.
- The voltage gated potassium ion channels now open.
- Potassium ions diffuse out of the axon down an electrochemical gradient.
- The sodium ion channels close.
- Hyperpolarisation occurs.
- But the sodium potassium pump then restores the resting potential by actively transporting 3 Na+ out of the axon and 2K+ into the axon.
